The present invention relates generally to motors and/or generators, and more particularly to a motor and/or generator operating on the reluctance principle, and having the following features:
a) the stator has sector stators (SS) which are distributed over the circumference of the rotor (R) and which are magnetically isolated from one another; PA1 b) each sector stator (SS) includes two toothed sector stator elements (SS1 and SS2, respectively) which are arranged one behind the other with an axial separation (a) and have common power windings (winding strands S1-S4) which are accommodated in slots between the stator teeth (SZ); PA1 c) each sector stator element (SS1 or SS2, respectively) in each case opens into radially projecting pole limbs (PS1 and PS2, respectively) which can in each case be excited in the direction of opposite polarity by an excitation winding part (EW1 or EW2, respectively) which loops around them, and which pole limbs (PS1 and PS2, respectively) are connected radially on the outside by a magnetic return path yoke (J); and PA1 d) an axially magnetized permanent magnet arrangement (M), which is magnetized in the opposite direction to the winding excitation in the sector stator elements, is arranged in the axial separating space between the sector stator elements (SS1 and SS2, respectively).
A starter-generator operating on the principle of the stator-excited synchronous machine of sector construction, having the features a)-c) discussed above, is disclosed in EP-B1-0,103,821. A starter-generator having the features a)-d) above is disclosed in PCT/EP 91/00302.
In the first-mentioned case, which is disclosed in EP-B1-0,103,821, the sector-stator elements of a sector stator are mutually isolated from one another by means of an axial separating space. The cylindrical envelope surface of a flywheel, especially of the clutch of a motor vehicle internal combustion engine, which is also used as the rotor of the motor and/or generator is designed in the form of two toothed rotors which are arranged offset with a gap, with a specific axial separation.
According to PCT/EP 91/00302, an axially magnetized permanent magnet arrangement, which is magnetized in the opposite direction to the winding excitation in the sector stator elements, is arranged in the axial separating space between the sector stator elements, in such a manner that its magnetic field is closed axially/tangentially and radially in the yokes of the sector stator elements, radially via the stator teeth, the air gap and the offset rotor poles, and axially/tangentially via the rotor yoke. As a result of the interaction of the excitation, which can be controlled by the excitation winding parts, on the one hand, and the permanent magnetization provided by the permanent magnet arrangement, on the other hand, a reduction in the excitation winding copper is possible with the excitation being easily controllable, and an undesirable, large stray field, primarily between the end surfaces of the laminated cores, which are located axially one in front of the other, of the sector stator elements, can be avoided. On its rear, outer radial edge regions, the magnet arrangement is adjacent to and flush with the edge regions of the sector stator elements which rest thereon axially.
The present invention is directed to the problem of developing a motor and/or generator of the above-mentioned type in which additional protection against undesirable stray fluxes can be achieved.